Background Systemic lupus erythematosus (SLE) is a multisystem inflammatory autoimmune disease that evolves with periods of remission and exacerbation activity, whose intensity can be measured by the SLEDAI. This tool is complex and has limitations. The mean platelet volume (MPV) is a marker of platelet activation and has been shown to be associated with inflammation, which makes it a potential biomarker to aid in the assessment of disease activity in SLE.
Objectives To evaluate VPM in SLE patients at the active and inactive stages according SLEDAI and assess a possible correlation between VPM with SLEDAI, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement 3 (C3), and complement 4 (C4).
Methods This cross-sectional study consisted of 40 patients with SLE, according to American College of Rheumatology (ACR) classification criteria, that were evaluated in Rheumatology Clinic of the Hospital de Clínicas de Porto Alegre in the second half of 2015. Interview during medical consultation and medical chart review were used to collect demographic, clinical and laboratory data. Disease activity was assessed with SLEDAI and chronicity was assessed with SLICC damage index (SDI). The blood count and platelets are measured in automation equipment Sysmex XE 5000. Platelets are analyzed by impedance, and the mean platelet volume is an index calculated by the machine when the examination of platelets. VSG was carried out by automated method by capillary photometry kinetics, PCR and C3 and C4 complement were determined in automation by immunoturbidimetry with intensification of reaction particles. Comparisons between groups were made with t-test or Mann-Whitney test.
Results All patients studied were female, 25 (62.5%) were classified as European-derived, mean age was 42.7±12.6 years and the average age at diagnosis was 29.9±9.9 years. At the time of the study, the median (IQR) for SLEDAI was 1.50 (0.0,4.0) and for SDI was 0.0 (0.0,1.0). Patients were divided into two groups (SLEDAI=0 and SLEDAI>0). The VPM had an inverse significant correlation with SLEDAI (r=-0.38; p=0.01). However, the MVP did not correlate significantly with ESR, CRP, C3 and C4. Patients were divided into two groups (SLEDAI=0 and SLEDAI>0) and the results for classification criteria were similar, but lymphopenia was most prevalent in group SLEDAI>0.
Conclusions There is a correlation between the VPM and the SLEDAI in our SLE patients, making it a possible tool to be used in the evaluation of disease activity.
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Disclosure of Interest None declared